Remote sensing systems, such as radar, sonar, lidar, and/or other ranging sensory systems, are often used to assist in navigation by producing data and/or imagery of the environment surrounding a mobile structure, such as imagery representing above-surface and/or subsurface features critical to navigation of a watercraft over a body of water. In operation, a sensing system may calculate the distance to a target by measuring the time between a short burst of radio-frequency (RF) energy, transmitted as a series of pulses, and the return of a reflected echo.
The transmitted RF pulses are typically generated using a pulse amplifier. Generally, the operating bias point of an amplifier is set to a value that provides a compromise between efficiency and distortion. Various operating modes, with their corresponding bias points are described in literature for example Class A, B, C & D amplifiers. The class the amplifier operates in is largely determined by the DC quiescent (no applied signal) current in the amplifier.
In continuously operating amplifiers the signal current and bias current can be controlled by separating them in frequency. In pulsed amplifiers, for efficiency reasons, it is not desirable to apply the quiescent bias between pulses, as it wastes energy and heats up the device. As a result, the bias and operating signals are both pulses and the device currents are both fluctuating. There is a continued need for improved systems and methods for setting and correcting the bias point of pulsed power amplifiers.